Research On Sinusoidal-wave Control Method For Brushless DC Motor

Brushless DC motor has advantages of simple structure, easy maintenance, good speedperformance and high efficiency, which have been widely used in industrial and commercial fields.Brushless DC motor is mostly driven by120°square-wave control method. Under this controlmethod, the output torque contains torque ripple, which results in a larger motor noise. The newsinusoidal-wave drive method is widely used in recent years with rapid development, which hasadvantages of small output torque fluctuations, low operation noise. The research on sinusoidal-wavecontrol method for brushless DC motor has important theoretical significance and practical value.In this thesis, a simulation and experimental study on several key technologies such as the rotorspeed and rotor position estimation, direct sinusoidal-wave starting control strategy and the phaseadvance angle compensation is performed, and estimation algorithm of rotor information based onHall sensor is researched emphatically.A novel estimation scheme for sensing rotor speed and rotor position is presented based on theanalysis of first-order and second-order estimation algorithms. The novel scheme aims to improve theestimation precision of rotor speed and rotor position during acceleration and deceleration phase.Gray prediction algorithm based on GM(1,1) model is used to get the time sequences of the Hallsectors. In order to realize sinusoidal-wave drive for brushless DC motor, the rotor speed and rotorposition information are calculated according to the predicted time value of the hall sector. Comparedto first-order and second-order estimation algorithms, the rotor position based on gray predictionalgorithm is more precise during acceleration and deceleration phase.An experimental platform of brushless DC motor control system using MC56F8013digitalsignal controller as the core chip is used to test the performance of the sinusoidal-wave controlstrategy, and sinusoidal-wave control experimental results are compared with test results ofsquare-wave control under the same conditions. Experimental results show that the designedsinusoidal-wave control system is stable and reliable, has good control performance, and is suitablefor applications where have strict requirements of cost and noise.